US3614961A - Method of generating vibrations in the sonic and ultra-sonic frequency ranges and devices for carrying said method into effect - Google Patents

Abstract

A METHOD OF GENERATION OSICLLATIONS IN FLUIDS COMPRISES DIRECTING TO FLUIDS STREAMS THROUGH NOZZLES AT AN ACUTE ANGLE WITH ONE ANOTHER TO A DEFLECTING BLADE DISPOSED AT THE POINT OF INTERSECTION OF THE TWO STREAMS OF FLUID FED FROM THE NOZZLES SO AS TO DEFLECT THE STREAMS, THE BLADE FORMING AN ACUTE ANGLE WITH EACH OF THE NOZZLES AT THE POINT OF INTERSECTION OF THE STREAMS. THE NOZZLES MAY BE FORMED BY SPIRAL STREAMS ARRANGED AROUND A DISCHARGE PORT WITH OVERLAPPING CENTRAL PORTIONS SERVING AS THE DEFLECTING BLADES.

Description

Oct. 26, 1971 N. NEKRASOV EI'AL 3,614,961

METHOD OF GENERATING VIBRATIONS IN THE SONIC AND ULTRA-SONIC FREQUENCY RANGES AND DEVICES FOR CARRYING SAIDMETHOD INTO EFFECT Filed Aug. 13, 1968 3 Sheets-Sheet 1 I I III IIIIIH A O t. 26, I971 N. NEKRASOV EI'AL 3,614,961

METHOD OF GENERATING VIBRATIONS IN THE SONIC AND ULTRA-SONIC FREQUENCY RANGES AND DEVICES FOR CARRYING SAID METHOD INTO EFFECT 7 Filed Aug. 13. 1968 3 Sheets-Sheet 2 Oct. 26, 1971 N. NEKRASOV ETAL 3,614,961

METHOD OF GENERATING VIBRATIONS IN THE SONIC AND ULTRA-SONIC FREQUENCY RANGES AND DEVICES FOR CARRYING SAID, METHOD INTO EFFECT Filed Aug. 13, 1968 3 Sheets-Sheet 3 United States Patent METHOD OF GENERATING VIBRATIONS IN THE SONIC AND ULTRA-SONIC FREQUENCY RANGES AND DEVICES FDR CARRYING SAID METHOD INTO EFFECT Nikolai Nikolaevieh Neln'asov, Ul. Gagarina S-a, kv. 45; Vasily Leonidovich Kazansky, Per. Chekhova 2, kv. 1; and Sergei Pavlovich Kirichenko, Ul. Kuiuzova 22, kv. 52, ail of Novokuibyshevsk, U.S.S.R.; and Nikolai Nikiforovich Tsyganov, Pos. Zavodskoi, ul. Kievskaya 4, kv. 4; and Alexei Alexandrovich Sergeichev, Ul. Tsyolkovskcgo 10, kv. 28, both of Syzran, U.S.S.R.

Filed Aug. 13, 1968, Ser. No. 752,272 Int. Cl. F150 1/16 US. Cl. 13781.5 4 Claims ABSTRACT OF THE DISCLOSURE A method of generating oscillations in fluids comprises directing two fluids streams through nozzles at an acute angle with one another to a deflecting blade disposed at the point of intersection of the two streams of fluid fed from the nozzles so as to deflect the streams, the blade forming an acute angle with each of the nozzles at the point of intersection of the streams. The nozzles may be formed by spiral streams arranged around a discharge port with overlapping central portions serving as the deflecting blades.

This invention relates to ultrasonic vibration generators, and to a method of generating sonic and ultrasonic oscillations as well as to devices for carrying out this method.

One of the known methods of production of sonic and ultrasonic oscillations consists in continually introducing a flow of gas or fluid to impinge on diaphragms or on plates and rods mounted so as to be free to vibrate.

Interaction of the gas or fluid flow with the bafl'le (plate, rod or diaphragm) results in producing ultrasonic oscillations arising due to swirling action or pulsation of the flow.

When the flow pulsation frequency coincides With the natural vibration frequency of the baffle (plate, rod or diaphragm), it causes resonant oscillations of the baflie and the flow, which are then propagated into the adjoining medium.

Disadvantages inherent in this method of generating sonic and ultrasonic oscillations and in devices for carrying it into effect, are as follows: instability of the vibration frequency and power arising from alteration of the gas or fluid volumetric flow rate or from dimensional variations of the battle (plate, rod or diaphragm). These changes in the oscillation frequency, intensity, and power are due to pressure variation in the gas or fluid flow or to partial destruction (i.e. the dimensional variations) of the baflle by abrasive particles contained in the flow.

Another known method for the production of sonic and ultrasonic oscillations consists in forcing a gas flow into a hollow chamber (resonator) at an ultrasonic velocity. A disadvantage of this method is the impossibility to generate sonic and ultrasonic oscillations by utilizing the energyy of a fluid flow, especially that of a combination of fluid and gas flows differing in their physical characteristics, since in this case the hollow chamber (resonator) should be of a very complicated design.

Patented Oct. 26, 1971 ice An object of the present invention is to avoid these dis advantages and to provide a method of generating ultrasonic vibrations, which ensures vibration frequency and power adjustment over relatively wide ranges due to the most eflicient utilization of the gas or fluid flow energy, and which also affords a simultaneous utilization of a fluid or gas and their suspension and aerosols with solid matter as a vibrating medium, the dependence of sonic and ultrasonic vibrations upon dimensional variations of the resonators (plates, rods, diaphragms and hollow chambers) being eliminated.

According to the invention said object is achieved by a method of generating oscillations in the sonic and ultrasonic frequency ranges by means of a flow of fluid or gas, which consists in continually introducing at least two streams running at an acute angle to each other to impinge on a baflie which deflects them, said baffle being fixedly mounted at the place where the two streams melt so that the joint flow is directed at an acute angle to each of the meeting streams.

When the two streams run against each other, they cause alternate retardation of each other at the baffle, which gives rise to pulsations of the stream at a definite repetition frequency at the place of retardation with a subsequent propagation of the arising ultrasonic vibrations through the reflected joint fluid or gas flow.

A device for carrying out the above method, i.e. a vibration generator, comprises at least two nozzles mounted at an acute angle to each other, past which nozzles 21 blade is provided, located at the point of meeting of the two streams of gas or fluid fed from said nozzles, so as to deflect said streams, said blade being inclined at an acute angle with each of the nozzles at the point of meet ing of said streams.

According to the present invention, in a preferred embodiment of the vibration generator, it is expedient to have at least the nozzles formed by identical spiral screens uniformly arranged around a window provided in the generator bottom piece for the vibrating medium to dis charge. The adjacent portions of these screens overlap each other by less than within the central angle, whereas the portions of each screen located the nozzles serve as deflecting blades which are inclined at an acute angle with each of the nozzles at the points of meeting of the streams fed from said nozzles.

As to a vibration generator designed for transmitting oscillations to a medium which is not to be mixed with the fluid or gas streams fed to the generator, a diaphragm for imparting oscillations to the medium, which takes no part in producing the oscillations is mounted for expedience in front of the window for discharging the vibrating medium.

When vibration generators are used in a sonic or ultrasonic mixer for mixing liquid or gaseous fluids differing in physical characteristics, it is desirable to mount these generators in succession along the flow of the agents being mixed, which serve as vibrating media and have the same direction of circulation for all of said generators.

To atomize liquid in a gas or steam flow by utilizing sonic or ultrasonic oscillations for producing small and uniformly sized droplets of liquids or their suspensions with solid matter, it is expedient to arrange vibration generators in succession along the flow of the atomized 3 liquid or liquids, the atomizing agent being fed to the last generator, the direction of the vibrating medium circulation for all the generators being the same.

When vibration generators are used in fuel burners in which besides the production of fine and uniformly sized droplets of the liquid fuel, there is a necessity to provide a uniform distribution of the atomized fuel throughout the entire torch volume as well as a high torch turbulization, it is expedient to mount at least three generators in succession along the dispersed fuel flow, so that the fuel is fed to the first generator, and a dispersing agent (steam, air, gas) is fed to the rest of them, the directions of circulation in the adjoining generators through which the dispersing agent is fed being opposite to one another.

The test ultrasonic fuel burner made according to the present invention provides the dispersion of fuel to droplets less than 15 microns in size (more than 85% of their total volume) under a pressure of 4 to 6 atm. gauge for the fuel and of 4 to atm. gauge for the dispersing agent (air, steam), and with the air-to-fuel ratio of 0.2:1 or the steam-to-water steam ratio of 0.1 1. The average and maximum droplet sizes are the same even when the fuel expenditure becomes 1.5 to 2 times as much as the normal one, with the expenditure of the dispersing agent (air, steam, gas) being constant. Moreover, the torch noise and the unit components vibration were insignificant due to the high frequency of the torch vibrations.

The accompanying drawing illustrates possible embodiments of the vibration generator and devices designed for realizing the method provided by the present invention, wherein:

FIG. 1 is a schematic diagram illustrating the arrangement of the generator nozzles and wall involved in producing sonic and ultrasonic oscillations;

FIG. 2 is a schematic diagram of the ultrasonic generator or shown in an axonometric projection;

FIG. 3 is a central longitudinal section view of the ultrasonic generator for transmitting oscillations to a medium isolated from the internal cavity of the generator;

FIG. 4 shows a central longitudinal section view of the sonic (ultrasonic) mixer utilizing the vibration generator of the present invention;

FIG. 5 shows a central longitudinal section view of the sonic (ultrasonic) fluid sprayer utilizing the vibration generator of the present invention; and

FIG. 6 shows a central longitudinal section view of the ultrasonic liquid fuel burner utilizing the vibration generator of the present invention.

The principle of generating sonic and ultrasonic oscillations consists in the following. A fluid or gas flow is equally divided into two streams A and B (FIG. 1) which have identical characteristics such as pressure, velocity, and flow rate, these two streams are directed through two identical nozzles 1 (having equal-area orifices) arranged at an acute angle (a) to each other. Being fed through the nozzles, these separated streams of fluid or gas meet at a deflecting blade 2 mounted fixedly at an acute angle (/3 and 7 respectively) to each of the streams, which are alternately retarded at the point of their meeting due to pressure increase in the fluid or gas streams in front of the outlets of nozzles 1.

The alternate and equally timed retardations of the streams meeting at the stationary befile give rise to pulsation of the jointly reflected fluid or gas flow. The appearance of the rhythmic pulsations causes the generation of sonic or ultrasonic (which depends on the velocity of the streams) vibrations propagating over the reflected flow.

A sonic or ultrasonic vibration generator 3 (FIG. 2) has ports 4 provided in the walls of a chamber 5. A fluid or gas flow fed through these ports is uniformly distributed throughout the chamber and forced to the inlets of the nozzles 1 formed of identical arcuate partitions or spiral screens 6 which are in effect the portions of the Archimedean spiral, uniformly arranged around a port 7 provided in a generator bottom 8 for the vibrating medium to discharge. The adjacent portions of the screens 6 overlap each other by less than of the central angle, whereas the portions of each screen located between the nozzles serve as deflecting blades '2, which are inclined at an acute angle with each of the nozzles at the points of meeting of the fluid or gas streams fed from said nozzles. While clirected against each other at the blades, the streams are alternately retarded under the influence of centrifugal force and velocity, which causes rhythmic and alternate in time pulsation in these streams. The pulsating joint flow is expelled from the generator through the port 7.

When the vibration generator is used for transmitting oscillations to a medium (liquid or gas), which is for some reason not to be mixed with the fluid or gas flow involved in producing these sonic and ultrasonic oscillations, there is to be mounted a diaphragm 9 (FIG. 3) in front of the generator port 7 for discharging a vibrating medium, said generator being fully discussed above in connection with FIG. 2.

To utilize the energy of sonic and ultrasonic oscillations for mixing and emulsifying liquids and or gases differing in their physical and chemical characteristics, a mixer 10 (FIG. 4) incorporates three vibration generators 3a, 3b, 30, whose operating principle is comprehensively discussed above with reference to FIG. 2. These generators are mounted in succession along the flow of the mixing liquids and or gases pumped through pipes 11, 12, 13. The directions of circulation of the fluid or gas flows are identical for all the generators, involved, whereas the flows of the vibrating fluid or gas are discharged through the ports 7 in the bottoms of the generators to freely pass from one generator to another so as to get into the zones of the most intensive sonic and ultrasonic oscillations, wherein they are mixed and then forced through a pipe 14 as a joint flow to be further utilized.

It is common knowledge that a droplet size, either for liquid or for mixture of liquids dispersed with the aid of some gas or steam, depends upon the amplitude and frequency of vibrations imparted to a dispersed liquid and to a dispersing gas. To utilize the effect of sonic and ultrasonic oscillations for dispersing liquid or liquids, a sprayer 15 (FIG. 5), made for the purpose in accordance with the present invention, has three vibration generators 3d, 3e, 3f which are discussed herein above with respect to FIG. 2, said generators being arranged in succession along the flow of the dispersed liquid, only the last generator 3 receiving gas for dispersion, the initial ones 3d, 3e being used for mixing only. The directions of the flow circulation for all the generators are identical, and the joint flow of the dispersed liquid and of the dispersing gas is issued through a profiled nozzle 16.

To provide highly dispersed and agitated flow of atomized fuel to be burnt up in an ultrasonic fuel burner 17 (FIG. 6) with the help of the energy of ultrasonic oscillations, use is made of three vibration generators 3g, 3h, 3k, which are discussed herein above with reference to FIG. 2, said generators being mounted in succession along the liquid fuel flow, the fuel being fed to the first generator, a dispersing agent to the rest of them. The directions of flow circulation in the adjoining generators through which the dispersing agent is fed are opposite to each other. The atomized fuel is fed into a furnace through a changeable profiled nozzle 18.

What is claimed is:

1. A vibration generator comprising a housing, said housing being provided with an inlet port and a discharge port, at least two arcuate partitions spaced from said inlet port and surrounding said discharge port, said arcuate partitions being spaced from one another, each of said arcuate partitions including a first portion and a second portion, said first portion of said arcuate partitions arcuately overlapping said second portion of the other of said arcuate partitions and constituting thereby opposing nozzles for passing opposing fluid streams, said second portion of said arcuate partitions constituting opposing blades each operatively associated with an opposing one of said nozzles for deflecting the opposing fluid streams into interaction with one another.

2. A vibration generator as claimed in claim 1 including a plurality of inlet ports corresponding in number to the number of said partitions.

3. A vibration generator as claimed in claim 2, wherein said arcuate partitions include corresponding portions equidistantly spaced from said discharge port, and have respective concavities opposing one another.

4. A vibration generator as claimed in claim 3, wherein said first portion of said arcuate partition overlaps said second portion of said arcuate partitions arcuately at an acute angle.

References Cited SAMUEL SCOTT, Primary Examiner US. Cl. X.R.

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